If an abbreviation or acronym that readers may not immediately recognize is to be used more than once, put it in brackets at first mention, e.g. Association of Chief Police Officers (ACPO), Seasonal affective disorder (SAD). This saves people having to search back through the article to find the original reference.

Use common sense; however, it is not necessary to spell out well-known ones such as EU, UN, CIA, FBI, CD, NASA, etc.

Cap up single letters in such expressions as "C-list", "F-word", "the word assassin contains four S's", etc.

'"Affect" and '"effect'" have no senses in common. As a verb, '"affect" is most commonly used in the sense of "to influence", e.g. "how smoking affects health". As a noun, "effect" means "to bring about or execute", e.g. "layoffs designed to effect savings". Thus, the sentence "These measures may affect savings" could imply that the measures may reduce savings that have already been realized, whereas the sentence "These measures may effect savings'" implies that the measures will cause new savings to come about.[1]

Apostrophes

They indicate a missing letter or letters ("can't", "we'd") or a possessive ("David's book").

Contractions can affect the tone of an article and make it appear informal and even inelegant: "what's more" may work but "what is more" may be more appropriate.

The possessive in words and names ending in 's' normally takes an apostrophe followed by a second 's', e.g. Jones's, James's, but be guided by pronunciation and use the plural apostrophe where it helps, e.g. Mephistopheles', Waters', Hedges' rather than Mephistopheles's, Waters's, Hedges's.

Plural nouns that do not end in 's' take an apostrophe and 's' in the possessive, e.g. "children's games", "old folk's home", "people's republic", etc.

Use apostrophes in phrases such as "two days' time", "12 years' imprisonment", and "six weeks' holiday" – where the time period (two days) modifies a noun (time) – but not in "nine months pregnant" or "three weeks old" – where the time period is adverbial (modifying an adjective such as pregnant or old). If in doubt, test with a singular such as "one day's time" or "one month pregnant".

As or since?

"As" is causal: "I cannot check the online style guide as the connection is down".

"Since" is temporal: "Luckily, I have had the style book on my desk since it was published".

Average, mean, and median.

Although we loosely refer to the "average" in many contexts, e.g. pay, there are two useful averages worth distinguishing.

What is commonly known as the "average" is the "mean": "Everyone's wages are added up and divided by the number of wage earners". The "median" is described as "the value below which 50% of employees fall", i.e. it is the wage earned by the middle person when everyone's wages are lined up from smallest to largest. (For even numbers, there are two middle people, but you calculate the mean average of their two wages.)

The "median" is often a more useful guide than the "mean", which can be distorted by figures at one extreme or the other.

C

Colon

Use this between two sentences, or parts of sentences, where the first introduces a proposition that is resolved by the second, e.g. "Fowler put it like this to deliver the goods invoiced in the preceding words".

A colon should also be used (rather than a comma) to introduce a quotation, e.g. "He was an expert on punctuation", or to precede a list, e.g. "He was an expert on the following: the colon, the comma, and the full stop."

This is an example of the tendency to use a semi-colon where only a colon will do: "Being a retired soap 'treasure' must be a bit like being in the army reserves; when a ratings war breaks out, it's time to dust off your uniform and wait by the phone."

There is a distinction between a colon and a semicolon; many writers seem to think they are interchangeable, but to make it clear they are not.

A misplaced comma can sabotage a sentence, as in this example: "Neocon economists often claim a large, black economy turbo-powers growth..." (The writer was talking about a big, black economy, not a big and black one, which is not the same.)

Contractions

Do not overuse contractions such as "aren't", "can't", "couldn't," "hasn't", "don't", "I'm", "it's", and "there's"; while they might make a piece more colloquial or easier to read, they can be an irritant and a distraction, and make a serious article sound frivolous.

H

Hyphens

Use one word whenever possible; hyphens tend to clutter up text (particularly when the computer breaks already hyphenated words at the end of lines).

Inventions, ideas, and new concepts often begin life as two words, then become hyphenated, before finally becoming accepted as one word. Why wait? "Wire-less" and "down-stairs" were once hyphenated.

Words such as "handspring", "madhouse", and "talkshow" are all one word, as are" thinktank" (not a tank that thinks), "longlist" (not necessarily a long list), and "shortlist" (which need not be short).

Prefixes such as 'macro-', 'micro-', 'mega-', 'mini-', 'multi-', 'over-', 'super-', and 'under-' rarely need hyphens. Examples are listed separately. Follow http://www.dictionary.com when a word or phrase is not specifically listed in this guide.

There is no need to use hyphens with most compound adjectives, where the meaning is clear and unambiguous without, e.g. "civil rights movement", "financial services sector", "work inspection powers", etc.

Hyphens should, however, be used to form short compound adjectives, e.g. "two-tonne vessel", "stand-up comedian"," three-year deal", "19th-century artist", etc.

Also use hyphens where not using one would be ambiguous, e.g. to distinguish "black-cab drivers come under attack" from "black cab-drivers come under attack".

Do not use hyphens after adverbs ending in '-ly', e.g. "politically naive", "wholly owned", but when an adverb is also an adjective, e.g. "hard". The hyphen is required to avoid ambiguity – it's not a "hard, pressed person", but a "hard-pressed one"; an "ill-prepared report", rather than an "ill, prepared one".

Use hyphens with short and common adverbs, e.g. "much-needed grammar lesson", "well-established principle of style" (note though that in the construction "the principle of style is well established" there is no need to hyphenate).

I

If not

This can be ambiguous. Does "it is the most beautiful castle in France, if not the whole of Europe" mean "and maybe in the whole of Europe" or "but not in the whole of Europe"?

Into or in to?

One word if you go "into a room", but two words in such sentences as "I called in to complain", "I listened in to their conversation", and "I went in to see my friend".

It's or its

"It's" is the shortened form of "it is" or "it has", e.g. "it's a big dog"; "it's been ages since I saw her". "Its" is the possessive form of "it", e.g. "the dog is eating its bone".

L

M

May or might?

"May" implies that the possibility remains open whereas "might" suggests that the possibility no longer remains open. "They may have played tennis, or they may have gone boating" suggests I don't know what they did; "they might have played tennis if the weather had been dry" means they didn't, because it wasn't.

N

No doubt that, no question that

These are opposites, e.g. "There was no doubt that he was lying" means he was lying; "There was no question that he was lying" means he wasn't, although the two are routinely confused.

No one

Not "no-one".

Numbers

When used within a sentence, spell out from one to nine; integers from 10 to 999,999 thereafter use m or bn for sums of money, quantities, or inanimate objects in copy, e.g. "£10m", "5bn tonnes of coal", "30m doses of vaccine" – but million or billion for people or animals, e.g. "1 million people", "3 billion rabbits", etc; spell trillion in full at first mention, then tn; in headlines use m, bn, or tn.

P

Pronunciation

If a word is too difficult to pronounce, the correct pronunciation isn't something most people know, or the word is not part of the English language, then the correct IPA pronunciation (if not English) in the Merriam-Webster pronunciation (if English or a place name) should be provided. (Along with a recording of the word being said clearly and correctly.)

Leave some silence at the end of a recording for browsers and players which truncate sound files.

Q

Quotation marks

Use double quotes at the start and end of a quoted section, with single quotes for quoted words within that section. Place full points and commas inside the quotes for a complete quoted sentence, otherwise the point comes outside, e.g.

but: "Anna said updating the guide was 'a difficult and time-consuming task'."

When beginning a quote with a sentence fragment that is followed by a full sentence, punctuate according to the final part of the quote, e.g. The minister called the allegations "blatant lies. But in a position such as mine, it is only to be expected."

For parentheses in direct quotes, use square brackets.

R

Re or re-?

Use 're-' (with hyphen) when followed by the vowels 'e' or 'u' (not pronounced as "yu"), e.g. "re-entry", "re-examine", "re-urge".

Exceptions are "re-read" or where confusion with another word would arise, e.g. "re-cover"/"recover", "re-form"/"reform", "re-creation"/"recreation", "re-sign"/"resign".

S

Self-control, self-defense, self-esteem, self-respect

These are hyphenated.

Semicolon

Used correctly, the semicolon is a very elegant compromise between a full stop (too much) and a comma (not enough). "Some reporters were brilliant; others were less so".

Subject-verb agreement

"RED is" or "BLU has" rather than "RED are" or "BLU have".

T

That or which?

"That" defines, "which" informs:

"This is the house that Jack built, but this house, which John built, is falling down".

This and that

"That was then, but this is now"; "this looks forward, that looks back"; a man showing his son and heir the lands lying in front of them says, "One day, son, all this will be yours." and then he points behind him to the house and says, "But that remains mine".

U

Uber

No accent if you are saying something like "uber fast", but use the umlaut if you are quoting German, i.e. Medic responses. The normal transliteration of the 'ü' ('u' with a dieresis representing an umlaut) when used in writing systems without diacritics (such as airport arrival boards, older computer systems, etc.) is 'ue', not just 'u'; however, the English language use of the word "uber" is considered a new word distinct from "ueber". When used in conjunction with another word, it should be written as an individual word and not hyphenated (example: "uber defense" not "uber-defense"). An "ÜberCharge" is the name of the effect from the Medigun in TF2, and as such should be capitalized (see TF2 Wiki Style guide). Also note that the contractions "uber'ed" or "uber'd" should be avoided and "ÜberCharged" used instead.

Y

y or ie?

As a general rule '-y' is an English suffix whose function is to create an adjective (usually from a noun, e.g. "creamy"); '-ie' was originally a Scottish suffix, whose function is to add the meaning of "diminutive" (usually from a noun, e.g. "beastie").

So in most cases where there is a dispute over whether a noun takes a '-y' or an '-ie' ending, the correct answer is '-ie', e.g. "She's a girly girl, but she's no helpless girlie". Think also "scrunchie", "beanie", "nightie", "meanie",... There are exceptions ("a hippy", "an indie band"), but where specific examples are not given, use '-ie' for nouns and '-y' for adjectives.